Development and validation of a new patient-reported outcome measure for peripheral nerve disorders of the hand, the I-HaND© Scale.

Following guidelines from the Patient-Centred Outcomes Research Institute and using a mixed methods study, a new patient-reported outcome measure (PROM) for both nerve trauma and compression affecting the hand, the Impact of a Hand Nerve Disorders (I-HaND) Scale, was developed. Face-to-face interviews with 14 patients and subsequent pilot-testing with 61 patients resulted in the development of the 32-item PROM. A longitudinal validation study with 82 patients assessed the psychometric properties of the I-HaND. Content and construct validity was confirmed by cognitive interviews with patients and through principal component analysis. The I-HaND has high internal consistency (α = 0.98) and excellent test-retest reliability (intraclass correlation coefficient = 0.97). Responsiveness statistics showed that the I-HaND can detect change over 3 months and discriminate between improvers and non-improvers. We conclude that the I-HaND can be used as a PROM for people with a range of hand nerve disorders.